Electron–electron interactions between ELF basins

The electrostatic repulsions among the electrons that populate different attraction basins of the electron localization function (ELF) are numerically obtained for a number of simple test molecules. Differences in these interbasin repulsions are shown to provide a map onto the Gillespie–Nyholm rules of the valence shell electron pair repulsion model, and the reasons behind this correspondence are briefly analyzed. We think that these repulsion parameters, including the inter-basin exchange energy, which we relate to resonance and conjugation, open new avenues towards more quantitative ELF analyses.